A coupler device for a forward viewing endoscope comprises a main body having a proximal end configured to attach to the distal end portion of the endoscope and a distal end portion that at least partially seals the distal end portion of the scope and allows for viewing of the surgical site. The coupler device may include a flexible working channel extension for attachment to the working channel of the endoscope. The coupler device provides a protective cover to reduce the ingress of debris, fluid, bacteria, or other unwanted matter from the working end of the endoscope which could lead to infection and decreased performance of the scope. A kit for use in an endoscopic procedure on a patient comprises the coupler device and an end viewing endoscope having a working channel, a light and a camera lens.
